Lubrication device of engine for reducing oil leakage

ABSTRACT

A lubrication device of an engine includes a crankshaft supported and rotatably mounted by a main bearing and disposed at one side of a cylinder block, wherein the crankshaft includes a first main journal and a second main journal at a center in an axial direction, the first main journal being disposed between a first pin journal and a second pin journal, the second main journal being disposed between the second pin journal and a third pin journal, and two oil holes formed at the first main journal, wherein one of the oil holes is extended so as to supply oil to the first pin journal, and another oil hole is extended so as to supply oil to the second pin journal.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims under 35 U.S.C. §119(a) the benefit of priority to Korean Patent Application No. 10-2016-0031288, filed on Mar. 16, 2016 with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a lubrication device of an engine for reducing oil leakage, and more particularly, to an oil leak reduction type lubrication device of an engine for forming an optimal oil supply environment in order to prevent an unnecessary oil loss of an engine.

BACKGROUND

In a general vehicle engine, a crankshaft is a component for converting a reciprocating motion of a piston made by an expansion stroke (explosion stroke) to a rotational motion through a connecting rod and generating a reciprocating motion of the piston through the connecting rod on other strokes such that uninterrupted power generation is possible.

The crankshaft is mounted in a lower portion (crank case) of a cylinder block forming a frame of an engine so as to be rotated by a motion of the connecting rod, and a bearing is used for preventing abrasion occurring by friction generated from the rotational motion.

As the bearing, there exist main bearings rotatably supporting the crankshaft mounted to the lower portion of the cylinder block and con-rod bearings mounted between the crankshaft and the connecting rod.

In addition, a main gallery, which is an oil flow passage, is formed in the cylinder block and lubrication is performed by engine oil supplied through the main gallery.

The engine oil is supplied to a main journal (crank journal) of the crankshaft supported by the main bearing through the main gallery, the engine oil supplied to the main journal is transferred to a pin journal (crank pin) of the crankshaft supported by the con-rod bearing through an oil hole bored into the crankshaft.

Meanwhile, an ordinary crankshaft is configured such that an oil hole having a consistent structure is formed as a respective main journal and thus an oil supply amount transferred from all main journals to a con-rod bearing is to be uniform, such that it is difficult, or impossible, to optimize oil supply and there is a further problem of generating oil leaks.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

SUMMARY

The present disclosure has been made in an effort to provide an lubrication device of an engine having advantages of forming an optimal oil supply environment whereby leaks and losses of engine oil are minimized by combining a crankshaft to which a combination type oil hole structure is applied having main bearings of different shapes respectively having different specifications than each other.

In the present disclosure, an lubrication device of an engine includes a crankshaft, which is supported and rotatably mounted by a main bearing and is disposed at one side of a cylinder block, the crankshaft having a first main journal and a second main journal at a center in an axial direction, the first main journal being disposed between a first pin journal and a second pin journal, the second main journal being disposed between the second pin journal and a third pin journal; and two oil holes formed at the first main journal, in which one of the oil holes is extended so as to supply oil to the first pin journal, and the other oil hole is extended so as to supply oil to the second pin journal.

According to an embodiment of the present disclosure, one oil hole may be formed at the second main journal and be extended so as to supply oil to the third pin journal, the first main journal may be supported by a first main bearing having a slit hole so as to supply oil to the two oil holes and be rotatably mounted to a lower portion of the cylinder block, and the two oil holes formed at the first main journal may be disposed on one equal circumference with respect to a circumferential direction of the first main journal.

In addition, according to an exemplary embodiment of the present disclosure, the first main journal may be rotatably mounted and supported to a first bearing mounting portion of a plurality of bearing mounting portions which are formed at a lower portion of the cylinder block by a first main bearing, and an oil supply hole for supplying oil and an oil groove connected to the oil supply hole together may be formed at the first bearing mounting portion.

Further, according to an exemplary embodiment of the present disclosure, the second main journal may be rotatably mounted and supported to a lower portion of the cylinder block by a second main bearing having a hole structure to be same as the first main bearing, and a third main journal and a fourth main journal, which are formed at both sides in an axial direction of the crankshaft, may be respectively supported by a third main bearing and a fourth main bearing having a hole structure to be same as each other and be rotatably mounted to a lower portion of the cylinder block.

Referring to an oil leak reduction type lubrication device of an engine according to the present disclosure, engine oil loss by oil leak is decreased by preventing unnecessary oil leak and thus effects such as reduction of hydraulic pump capacity and improvement of engine fuel consumption can be gained as an optimal oil supply environment is made such that oil supply amount is optimized.

Other aspects and embodiments of the disclosure are discussed infra.

It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline and electric power sources.

The above and other features of the disclosure are discussed infra.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present disclosure will now be described in detail with reference to certain exemplary embodiments thereof illustrated the accompanying drawings which are given hereinbelow by way of illustration only, and thus are not limitative of the present disclosure, and wherein:

FIG. 1 is a view illustrating a crankshaft and main bearings according to exemplary embodiments of the present disclosure.

FIG. 2 is a view showing a bearing mounting portion of a cylinder block according to exemplary embodiments of the present disclosure.

FIG. 3 is a view illustrating the crankshaft of FIG. 1 at a different rotational angle than that shown in FIG. 1.

FIG. 4 and FIG. 5 are views for explaining a flow route of engine oil according to exemplary embodiments of the present disclosure.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the disclosure. The specific design features of the present disclosure as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present disclosure throughout the several figures of the drawing.

DETAILED DESCRIPTION

Hereinafter reference will now be made in detail to various embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings and described below. While the disclosure will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the disclosure to those exemplary embodiments. On the contrary, the disclosure is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the disclosure as defined by the appended claims.

The present disclosure will hereinafter be described to be easily realized by a person of an ordinary skill in the art.

Generally, an in-line 3 cylinder engine is an internal combustion engine having three cylinders in which a piston makes a reciprocal motion during an expansion stroke, and three pistons rotate a crankshaft via connecting rods.

The crankshaft is one of moving components of an engine for transforming a reciprocal motion of a piston to a rotational motion, and is moved and rotated together with the piston and the connecting rod as an explosion force (expansion force) of fuel acts to the piston.

FIG. 1 shows a crankshaft and main bearings of an in-line 3 cylinder engine, FIG. 3 shows the crankshaft at a different rotational angle, and FIG. 5 shows the crankshaft from a side view.

Referring to FIG. 1, a crankshaft 100 includes a plurality of main journals 110, 120, 130 and 140 (or crank journal) as a main shaft, a plurality of pin journals 150, 160, and 170 (crank pin) to which a big end of a connecting rod is mounted, and a plurality of crank arms 180 connecting the main journals 110, 120, 130 and 140 with pin journals 150, 160 and 170.

Though not shown, a piston is connected with a small end of an opposite end of the big end of the connecting rod, each piston is mounted to make a reciprocal motion in one of a plurality of cylinders formed in a cylinder block.

As shown in FIG. 3 and FIG. 5, together with FIG. 1, the crankshaft 100 is configured so that a first main journal 110 and a second main journal 120 are formed at a center in an axial direction (lengthwise direction, or along an axis of crankshaft rotation within an engine block), a third main journal 130 and a fourth main journal 140 is formed at both sides of an axial direction, the first main journal 110 is disposed between a first pin journal 150 and a second pin journal 160, the second main journal 120 is disposed between the second pin journal 160 and a third pin journal 170, the first pin journal 150 is disposed between the first main journal 110 and the third main journal 130, and the third pin journal 170 is disposed between the second main journal 120 and the fourth main journal 140.

Each main journal 110, 120, 130 and 140 and pin journal 150, 160 and 170 are integrated by being connected with one another through the crank arm 180, and a rotation of the crankshaft 100 is performed by a reciprocal motion of the piston connected with each pin journal 150, 160 and 170 through the connecting rod.

The arrangement structure of the main journals 110, 120, 130 and 140, the pin journals 150, 160 and 170, and crank arm 180 is clearly shown in a side view of the crankshaft 100 illustrated in FIG. 5.

Referring to FIG. 3 and FIG. 5, two oil holes 111 and 112 are formed at the first main journal 110, a first oil hole 111 of the two oil holes 111 and 112 is formed to be extended so as to supply oil to the first pin journal 150, and a second oil hole 112 is formed to be extended so as to supply oil to the second pin journal 160.

The first oil hole 111 is formed to an exterior circumference of the first pin journal 150 and the second oil hole 112 is formed to an exterior circumference of the second pin journal 160 so as to function to lubricate the connecting rod which is connected therewith by interposing a con-rod bearing (not shown) to exterior circumferences of the first and second pin journals 150 and 160.

In addition, the first oil hole 111 and second oil hole 112 are disposed on one equal circumference (a circumference comprising points positioned apart from one point on an axial line of the first main journal) with respect to a circumferential direction of the first main journal 110.

Further, the first main journal 110 is supported by a first main bearing 210 having a slit hole 211 for supplying oil to the first oil hole 111 and second oil hole 112 so as to be rotatably mounted to a lower portion of the cylinder block (referring to 200 of FIG. 2).

Referring to FIG. 1 and FIG. 4, the first main bearing 210 is formed by combining a first upper bearing 210 a and a first lower bearing 210 b, which have plate shapes having a half circle shape, to make a cylindrical shape, and the first upper bearing 210 a and the first lower bearing 210 b are mounted to a first bearing mounting portion 201 of the cylinder block 200 so as to rotatably surround the first main journal 110.

At the first upper bearing 210 a, a lubrication hole 212 to supply oil for lubrication of the first main journal 110 is disposed together with the slit hole 211 for supplying oil to the first oil hole 111 and the second oil hole 112.

The first main journal 110 supplies engine oil being supplied through the slit hole 211 to the first pin journal 150 and the second pin journal 160 through the first oil hole 111 and the second oil hole 112 when the first oil hole 111 and the second oil hole 112 are positioned on the slit hole 211 while the crankshaft 100 is rotated by a reciprocal motion of the piston.

Herein, the slit hole 211 is provided with a predetermined length for flowing a large amount oil therein to supply oil to the first oil hole 111 and the second oil hole 112. For example, the slit hole 211 is formed with a length to correspond to a distance between the first oil hole 111 and the second oil hole 112 on a circumference of the first main journal 110.

At this time, the first oil hole 111 and the second oil hole 112 are disposed on an equal line to a circumference of the first main journal 110 through which the slit hole 211 passes when the second main journal 120 rotates.

Next, referring to FIG. 1 and FIG. 5, one oil hole 121 is formed at the second main journal 120 to supply oil to the third pin journal 170. The oil hole 121 is formed to be extended from an exterior circumference of the second main journal 120 to an exterior circumference of the third pin journal 170 so as to function to lubricate the connecting rod connected therewith by interposing a con-rod bearing (not shown) to an exterior circumference of the third pin journal 170.

The second main journal 120 is supported by a second main bearing 220 having a slit hole 221 for supplying oil to an the oil hole 121 to be rotatably mounted to a lower portion of the cylinder block 200.

Referring to FIG. 1 and FIG. 4, the second main bearing 220 is mounted to a second bearing mounting portion 202 of the cylinder block 200 such that a second upper bearing 220 a and a second lower bearing 220 b, which have plate shapes having a half circle shape, rotatably surround the second main journal 120.

At the second upper bearing 220 a, a lubrication hole 222 to supply oil for lubrication of the second main journal 120 is disposed together with the slit hole 221 for supplying oil the oil hole 121.

It is unnecessary that the slit hole 221 is formed to be as long as the slit hole 211 of the first upper bearing 210 a, since a relatively large amount of oil supply is not required to the slit hole 221 of the second upper bearing 220 a. However, the slit hole 221 of the second upper bearing 220 a has the same size as the slit hole 211 of the first upper bearing 210 a by dualizing specifications of the main bearings mounted to the cylinder block 200 for using the first main bearing 210 and the second main bearing 220 with an equal specification, and using the third main bearing 230 and the fourth main bearing 240 with an equal specification.

In other words, the second main journal 120 is supported by the second main bearing 220 having a same hole structure as each other with the first main bearing 210 and is mounted to a lower portion of the cylinder block 200, and the third main journal 130 and the fourth main journal 140 formed at both sides in an axial direction of the crankshaft 100 are respectively supported by the third main bearing 230 and the fourth main bearing 240 having the same hole structure as each other and are mounted to a lower portion of the cylinder block 200.

As described above, an assembly process is simplified and cost are decreased by dualizing specifications of the main bearings.

An oil hole is not formed at the third main journal 130 and the fourth main journal 140. The main journals 130 and 140 are respectively supported by the third main bearing 230 and the fourth main bearing 240 and are rotatably mounted to a lower portion of the cylinder block 200.

Referring to FIG. 1 and FIG. 4, the third main bearing 230 is mounted to a third bearing mounting portion 203 of the cylinder block 200 such that a third upper bearing 230 a and a third lower bearing 230 b, which have plate shapes having a half circle shape, rotatably surround the third main journal 130, and the fourth main bearing 240 is mounted to the fourth bearing mounting portion 204 of the cylinder block 200 such that a fourth upper bearing 240 a and a fourth lower bearing 240 b, which have plate shapes having a half circle shape, rotatably surround the fourth main journal 140.

At the third upper bearing 230 a, a lubrication hole 232 to supply oil for lubrication of the third main journal 130 is disposed, and at the fourth upper bearing 240 a, a lubrication hole 242 to supply oil for lubrication of the fourth main journal 140 is disposed.

That is, the third main bearing 230 and the fourth main bearing 240 are provided with the same specification that only the lubrication holes 232 and 242 are disposed at the upper bearing 230 a and 240 a, and no slit hole is formed thereon.

The each main bearing 210, 220, 230 and 240 and main journal 110, 120, 130 and 140 reduce fluid friction with (engine oil) for the elements relatively sliding thereon.

Meanwhile, referring to FIG. 2, the cylinder block 200 is configured so that an oil groove 201 b is formed at only the first bearing mounting portion 201 to which the first main bearing 210 is mounted.

A main gallery (referring to 206 of FIG. 4) is formed as oil passage for flowing oil supplied from an oil pump (not shown) in the cylinder block 200, and oil supplied through the main gallery 206 is supplied to the first bearing mounting portion 201, the second bearing mounting portion 202, the third bearing mounting portion 203 and the fourth bearing mounting portion 204. A large amount of oil is relatively and intensively supplied to the first bearing mounting portion 201 to which the first main journal 110 having the two oil holes 111 and 112 is mounted.

Oil supplied at a large amount is supplied to the lubrication hole 212 together with the slit hole 211 of the first main bearing 210 through the oil supply hole 201 a formed and disposed at the first bearing mounting portion 201. An oil groove 201 b is formed at an edge portion of the oil supply hole 201 a for stably supplying a large amount of oil to the slit hole 211 and the lubrication hole 212.

The oil groove 201 b is formed with a long hole structure so as to be extended to a circumferential direction of the first bearing mounting portion 201, and thus a large amount of oil is stably supplied to the slit hole 211 and the lubrication hole 212 as oil supplied toward the first main bearing 210 through the oil supply hole 201 a is expanded along the oil groove 201 b.

As described above, oil supply is to be intensive to only the first main journal 110 transferring oil toward the first pin journal 150 and a relatively small amount of oil is supplied to the other main journals 120, 130 and 140 as the oil groove 201 b is formed at only the first bearing mounting portion 201 so that effects of optimizing oil supply amount and reducing load of an oil pump are gained. Thus, the capacity of the oil pump is optimized to be reduced such that enhancements of fuel consumption can be realized.

In addition, an oil groove is not formed at the second bearing mounting portion 202 and the third bearing mounting portion 203 and only the oil supply holes 202 a and 203 a are formed thereon, and oil is supplied to lubrication holes 222 and 232 of the second main bearing 220 and the third main bearing 230 through the oil supply hole 202 a and 203 a.

Referring to FIG. 2, in a case of the fourth bearing mounting portion 204, an oil groove 204 b having a slit groove shape is disposed together with an oil supply hole 204 a for supplying oil to the lubrication hole 242 of the fourth main bearing 240, but the oil groove 204 b as a structure for supplying oil to a different position of an engine is unrelated to lubrication of the fourth main bearing 240 and the fourth main journal 140 and the present disclosure is not limited thereto, so detailed description thereof will be omitted.

Meanwhile, a lower portion of the cylinder block 200 is generally called an upper crank case. Though it is not shown, an oil pan (not shown), which is called lower crank case, is coupled to a lower portion of the upper crank case, and lower bearings 210 b, 220 b, 230 b and 240 b of the first to fourth main bearings 210, 220, 230 and 240 are mounted and supported to the oil pan, and oil that completes lubrication falls to the oil pan to be collected.

In further detail, the crankshaft 100 is supported by a plurality of main bearings 210, 220, 230 and 240 and is rotatably mounted between the upper crank case and the lower crank case. The upper bearings 210 a, 220 a, 230 a and 240 a are mounted to the upper crank case side so as to receive oil from the main gallery 206 and the lower bearings 210 b, 220 b, 230 b and 240 b are mounted to the lower crank case side.

As described above, as engine oil is supplied to only the first main journal 110 and the second main journal 120 where oil distribution is required and engine oil is not supplied to the third main journal 130 and the fourth main journal 140 where oil distribution is not required in the present disclosure, unnecessary oil loss can be prevented. Simultaneously, capacity of the oil pump can be reduced and unnecessary oil loss is prevented by dualizing specifications of main bearings as oil hole structures for transferring oil are formed at only the first main journal 110 and the second main journal 120 so that optimal oil supply environment for reducing oil leaks may be made.

Although embodiments of the present disclosure are described in detail as above, it is apparent that the scope of the present disclosure is not limited to the embodiments described in detail and many variations and modifications made to the present disclosure by those skilled in the art using basic idea of the present disclosure as defined in the appended patent claims fall within the scope of the disclosure. 

What is claimed is:
 1. A lubrication device of an engine, comprising: a crankshaft supported and rotatably mounted by a main bearing and disposed at one side of a cylinder block, wherein the crankshaft includes a first main journal and a second main journal at a center in an axial direction, the first main journal being disposed between a first pin journal and a second pin journal, the second main journal being disposed between the second pin journal and a third pin journal; and two oil holes formed at the first main journal, wherein one of the oil holes is extended so as to supply oil to the first pin journal, and another oil hole is extended so as to supply oil to the second pin journal.
 2. The lubrication device of claim 1, wherein one oil hole is formed at the second main journal and is extended so as to supply oil to the third pin journal.
 3. The lubrication device of claim 1, wherein the first main journal is supported by a first main bearing having a slit hole so as to supply oil to the two oil holes and is rotatably mounted to a lower portion of the cylinder block.
 4. The lubrication device of claim 1, wherein the two oil holes formed at the first main journal are disposed on one equal circumference with respect to a circumferential direction of the first main journal.
 5. The lubrication device of claim 1, wherein the first main journal is rotatably mounted and supported to a first bearing mounting portion of a plurality of bearing mounting portions which are formed at a lower portion of the cylinder block by a first main bearing, and an oil supply hole for supplying oil and an oil groove connected to the oil supply hole together are formed at the first bearing mounting portion.
 6. The lubrication device of claim 5, wherein the second main journal is rotatably mounted and supported by the lower portion of the cylinder block by a second main bearing having a hole structure to be the same as the first main bearing, and a third main journal and a fourth main journal, which are formed at both sides in an axial direction of the crankshaft, are respectively supported by a third main bearing and a fourth main bearing having a same hole structure and are rotatably mounted to the lower portion of the cylinder block. 